Abstract
Studies of food microorganism domestication can provide important insight into adaptation mechanisms and lead to commercial applications. The Penicillium roqueforti fungus consists of four genetically differentiated populations, two of which have been domesticated for blue cheese-making, the other two thriving in other environments. Most blue cheeses are made with strains from a single P. roqueforti population, whereas Roquefort cheeses are inoculated with strains from a second population. We made blue cheeses in accordance with the production specifications for Roquefort-type cheeses, inoculating each cheese with a single P. roqueforti strain and using three strains from each of the four populations. The strain population-of-origin had a minor impact on bacterial diversity and none on the main microorganism abundance. The strains from cheese populations produced cheeses with higher percentages of blue area and larger amounts of desired volatile compounds. In particular, the Roquefort strains produced larger amounts of appealing aromatic compounds, in part due to their greater efficiency of proteolysis and lipolysis. The typical appearance and flavors of blue cheeses thus result from human selection on P. roqueforti, and the two cheese populations have acquired specific features. This has important implications for our understanding of adaptation and domestication, and for cheese improvement.
Competing Interest Statement
TC, MLP, SB, DR and MP have been employed by the funder SAS LIP which produces starters for fermented food products during the course of the study and therefore declare a competitive financial interest. None of them, except TC, played a role in the design decision, data analysis and interpretation, or in the decision to submit the work for publication. All other authors declare no conflict of interest.
Footnotes
↵* should be considered joint senior authors
The study of food microorganism domestication can bring important insights on adaptation mechanisms and have industrial applications. The Penicillium roqueforti mold is divided into four genetically differentiated populations, with two populations domesticated for blue-cheese making and two populations thriving in other environments. While most blue cheeses worldwide are made with strains from a single P. roqueforti population, the emblematic Roquefort cheeses are inoculated with strains of a second cheese-specific population. We made blue cheeses following Roquefort-type production specifications and by inoculating one strain in each cheese, overall using three strains of each of the four populations. The P. roqueforti population-of-origin of the strains had a minor impact on microorganism abundance and diversity. The strains from cheese P. roqueforti populations produced cheeses with higher percentages of blue area and higher quantities of desired volatile compounds. The Roquefort P. roqueforti population in particular produced higher quantities of appealing aromatic compounds, which was related to its most efficient proteolysis and lipolysis. The typical appearance and flavours of blue cheeses are thus the result of human selection on P. roqueforti and the two cheese populations have acquired specificities. This has important implications for our understanding of adaptation, domestication processes and for improving cheese production.